Engineers at NASA’s Synthetic Biology Initiative are creating the building blocks of life – or rather, using life to create building blocks. Instead of shipping construction materials for a theoretical base on Mars, scientists are developing microbes capable of creating the ingredients for bricks and mortar. Feeding on astronaut waste and the materials available to them on the red planet, these space bugs could be the first to colonize Mars.

When it comes to construction, i’s best to start from the ground up. A team led by Brown graduate Andre Burnier and Lynn Rothschild from the Ames Research Center in Moffett Field in California are using microbes to create substances that can be used for building material on Mars. They plan to use Sporosarcina pasteurii bacteria, which are organisms that feed on urea (a principle ingredient found in human urine) and excrete ammonium. The bacteria could consume astronaut waste, and the resulting ammonium would make the dusty Mars environment alkaline enough for calcium carbonate binding agents to form, creating a sort of cement. This cement could then be used to hold together the red, dusty soil on the ground to form bricks. The same material might also be used as a mortar to hold the bricks together. Through experiments, Burnier’s team found that it took about two weeks to make a brick with the strength of concrete.

This process bypasses the need to send heavy payloads of materials into space via rocket, conserving fuel and establishing biological pathways on Mars. Microbes weigh next to nothing, and they could be sustained by human waste. Plans to use other species of bacteria, such as an ancient cyanobactera named Anabaena, have been proposed to turn the carbon dioxide and nitrogen present in Martian air into sugars for energy.

“Every gram delivered to Mars or other planets translates into huge additional costs and energy demands,” said Paul Dear at the MRC Laboratory of Molecular Biology in Cambridge to the New Scientist. “Biology rather than physical engineering is the only realistic way to do things on a planetary scale.” However, robotic missions will still the main method of investigating the planet for the time being. As Dear noted, “It takes a lot of faith to trust your life to a bacterium.”